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Spectral Setups: Acquisition
To Use
Click the control that you want to change and use the multipurpose
knobs to adjust the values.
Behavior
Rec Length
(Record Length) is the total number of samples in the
waveform acquisition. The maximum record length depends on the
amount of memory. The record length determines the duration, which
is expressed in seconds. Samp Rate (Sample Rate) is the number of
acquisition samples per second. The faster the sample rate, the more
accurately the instrument can represent fine details in a fast signal.
The sample rate determines the acquisition duration, which is expressed in seconds. The usable
bandwidth of the signal equals one half the sample rate and is expressed in hertz.
Duration is the length of the acquired waveform in seconds. Adjusting the duration usually
changes the record length without changing the current sample rate.
Resolution is the time between sample points. Changing the resolution changes the record length
and the sample rate so that the selected duration setting remains constant.
Note
The acquisition controls interact with the gating and frequency domain controls; changing one set
of controls may change some of the other control settings.
Spectral Setups: Gating
To Use
Select the FFT window type from the Window Type list. Use the
multipurpose knobs to set the gating parameters.
Behavior
An FFT Window Type can help reduce spectral noise for many types of
signals. Some windows provide better frequency resolution at the expense
of better amplitude measurements. Other windows provide better
amplitude accuracy over frequency resolution. The choice of window also
affects the resolution bandwidth.
Gate Pos
(Gate Position) moves the gate that selects the data for the spectral waveform. The gate
position is the center point in the gate measured in seconds with respect to the trigger point.
In most cases the phase reference point is located at the center of the gated data. However, if you
use a Tek Exponential window, the phase reference point is at the 20% point of the gated data.
Gate Dur
(Gate Duration) sets the gate time duration in seconds. The default gate duration is the
duration of the entire waveform record. The resolution bandwidth is inversely proportional to the
gate duration.
Summary of Contents for TDS5000B Series
Page 36: ...36 AFTDS Differential Signal Adapter...
Page 280: ...280 Blackman Harris window...
